Satellites in telecommunications systems can use different types of orbits. Example orbits include geostationary orbits, Molniya orbits, elliptical orbits, and low Earth orbits. Satellites in low Earth orbit typically travel at an altitude between 160 km and 2,000 km above the Earth's surface. Satellites in low Earth orbit are not necessarily geosynchronous. Therefore, the satellite moves relative to a stationary receiver located near the Earth's surface. The movement of the satellite, either toward or away from the stationary receiver, creates a Doppler effect.